Leaves change color in the fall because the chlorophyll, the green pigment responsible for photosynthesis, breaks down as the days get shorter and temperatures cool. This breakdown reveals other pigments present in the leaf such as carotenoids, which produce yellow and orange hues, and anthocyanins, which are red pigments that develop in the fall. The change is triggered primarily by the shorter daylight hours and colder weather, signaling trees to stop producing chlorophyll so they can prepare for winter. The various pigments visible in fall give us the rich array of yellow, orange, red, and brown colors typical of autumn foliage. Weather conditions such as sunny days can enhance red pigment production, while wind and rain can accelerate leaf fall.
